Sine generation circuit, phase shift circuit and tint adjustment circuit
Summary by NHIP
Sine generation circuit
The circuit generates sine and reversed sine signals from an input angle using two differential transistors. It requires the input signal to remain between −0.8 and +0.8 radians while sharing a common emitter connection and a single current source.
Claim Score by NHIP
Abstract
A phase shift circuit includes a first sine generation circuit generating a sine-converted output signal (sin θ) of the phase shift input signal (θ) and a reversed sine-converted output signal (−sin θ) of the phase shift input signal (θ), a cosine generation circuit generating a cosine-converted output signal (cos θ) of the phase shift input signal (θ), a first multiplication circuit, a second multiplication circuit, a third multiplication circuit, a fourth multiplication circuit, a first addition circuit adding an output signal of the first multiplication circuit to an output signal of the second multiplication circuit, and a second addition circuit adding an output signal of the third multiplication circuit to an output signal of the fourth multiplication circuit. This configuration makes the construction of a phase shift circuit for tint adjustment simple because of a coordinate transformation embedded in the configuration.
Term
Term ended
Expired 28 November 2023, 2.8 years ago.
- Priority
- Filed
- Granted
- Expired
- Today
9 claims: 5 independent, 4 dependent
- 1A sine generation circuit comprising:a first differential transistor and a second differential transistor, an emitter of the first transistor and an emitter of the second transistor being electrically connected to each other;and a current source electrically connected to the emitters of both the first transistor and the second transistor, wherein an input signal (θ) is applied between a base of the first transistor and a base of the second transistor, the first transistor and the second transistor are configured so that a sine-converted output signal (sin θ) of the input signal (θ) is generated at a collector of the first transistor and a reversed sine-converted output signal (−sin θ) of the input signal (θ) is generated at a collector of the second transistor, and the input signal (θ) is below +0.8 radian and above −0.8 radian.
- 2A phase shift circuit shifting a phase of a coordinate input signal (x, y) by a phase shift input signal (θ) to generate a coordinate output signal (X, Y), comprising:a first sine generation circuit generating a sine-converted output signal (sin θ) of the phase shift input signal (θ) and a reversed sine-converted output signal (−sin θ) of the phase shift input signal (θ);a cosine generation circuit generating a cosine-converted output signal (cos θ) of the phase shift input signal (θ);a first multiplication circuit multiplying a first component of the coordinate input signal (x) by the cosine-converted output signal (cos θ);a second multiplication circuit multiplying a second component of the coordinate input signal (y) by the sine-converted output signal (sin θ);a third multiplication circuit multiplying the first component of the coordinate input signal (x) by the reversed sine-converted output signal (−sin θ);a fourth multiplication circuit multiplying the second component of the coordinate input signal (y) by the cosine-converted output signal (cos θ);a first addition circuit adding an output signal of the first multiplication circuit to an output signal of the second multiplication circuit, the first addition circuit providing a first component of the coordinate output signal (X);and a second addition circuit adding an output signal of the third multiplication circuit to an output signal of the fourth multiplication circuit, the second addition circuit providing a second component of the coordinate output signal (Y).
- 6Broadest claimClaim Score 55, average(NHIP)A tint adjustment circuit comprising:a chrominance signal demodulation circuit demodulating a chrominance signal of a television signal in accordance with a carrier of the television signal, the chrominance signal demodulation circuit outputting a first color difference signal and a second color difference signal;and a phase shift circuit receiving the first and second color difference signals from the chrominance signal demodulation circuit and shifting a phase of the first color difference signal for tint adjustment and a phase of the second color difference signal for tint adjustment.
- 8A tint adjustment circuit comprising:a chrominance signal demodulation circuit demodulating a chrominance signal of a television signal in accordance with a carrier of the television signal, the chrominance signal demodulation circuit outputting a first color difference signal (x) and a second color difference signal (y);a sine generation circuit generating a sine-converted output signal (sin θ) of an input signal (θ) for color tint adjustment and a reversed sine-converted output signal (−sin θ) of the input signal (θ);a cosine generation circuit generating a cosine-converted output signal (cos θ) of the input signal (θ);a first multiplication circuit multiplying the first color difference signal (x) by the cosine-converted output signal (cos θ);a second multiplication circuit multiplying the second color difference signal (y) by the sine-converted output signal (sin θ);a third multiplication circuit multiplying the first color difference signal (x) by reversed the sine-converted output signal (−sin θ);a fourth multiplication circuit multiplying the second color difference signal (y) by the cosine-converted output signal (cos θ);a first addition circuit adding an output signal of the first multiplication circuit to an output signal of the second multiplication circuit, the first addition circuit providing a first output signal (X);and a second addition circuit adding an output signal of the third multiplication circuit to an output signal of the fourth multiplication circuit, the second addition circuit providing a second output signal (Y), wherein the first output signal and the second output signal (X, Y) provide a pair of shifted color difference signals for tint adjustment.
- 9The tint adjustment circuit of claims 7 or 8 , wherein the sine generation circuit, the cosine generation circuit, the first multiplication circuit, the second multiplication circuit, the third multiplication circuit and the fourth multiplication circuit comprise a differential amplifier having a bipolar transistor.
Independent claims5
61 paragraphs in 4 sections, as filed
BACKGROUND OF THE INVENTION
00011. Field of the Invention
0002This invention relates to a sine generation circuit for obtaining a sin θ (sine-converted) output signal from an input signal (θ), specifically to a sine generation circuit comprising bipolar transistors. This invention also relates to a phase shift circuit used in a television set, specifically to a phase shift circuit comprising bipolar transistors. Additionally this invention relates to a tint adjustment circuit used in a television set, specifically to a tint adjustment circuit comprising the bipolar transistors.
00032. Description of the Related Art
0004A viewer of a television, in general, makes a tint adjustment of a chrominance signal by using external adjusting means, such as a volume dial, of the television set. For adjusting the tint, a demodulation axis (x-axis, y-axis) of the chrominance signal should be rotated in both directions. To rotate the modulation axis, the phase of a color carrier of 3.58 MHz applied to a modulator should be changed.
0005<figref idref="DRAWINGS">FIG. 6</figref> shows a tint adjustment circuit for changing the phase of the color carrier of 3.58 MHz. In <figref idref="DRAWINGS">FIG. 6</figref>, the color carrier is applied to an input terminal <b>1</b>, and a horizontal synchronous pulse is applied to a terminal <b>2</b>.
0006A burst separation circuit <b>3</b> extracts only a burst signal from the color carrier inputted from the input terminal <b>1</b> based on a horizontal synchronous pulse. The extracted burst signal is converted to a continuous wave of the burst by a continuous wave generation circuit <b>4</b> (CW generation circuit).
0007This continuous wave is applied to the demodulator <b>6</b> of the chrominance signal through a phase shift circuit <b>5</b>. The demodulator <b>6</b> receives the chrominance signal from a terminal <b>7</b> and demodulates a B-Y color difference signal and an R-Y color difference signal to terminals <b>8</b> and <b>9</b>. Two kinds of continuous waves are required to demodulate these two signals and the phase shift circuit <b>5</b> supplies two continuous waves used for the B-Y color difference signal and the R-Y color difference signal to the demodulator <b>6</b>.
0008Therefore, when a viewer changes the amount of phase shift of the phase shift circuit <b>5</b> using the external adjusting means, the tint of the chrominance signal can be adjusted based on the principal described above.
0009However, in the above circuit configuration, although the phase control as described above can be performed to the signal going through the demodulator <b>6</b>, phase control cannot be performed to the signal which does not go through the demodulator <b>6</b>. That is, although the tint adjustment can be performed to the modulated chrominance signal, the tint adjustment can not be performed to the chrominance signal after the demodulation.
0010When a DVD player is connected to a television set, a component signal (Y, Cb, Cr) is applied to the television set from outside. The chrominance demodulation has already been performed to such a signal. Thus, the tint adjustment can not be performed with the conventional circuit described above.
SUMMARY OF THE INVENTION
0011A sine generation circuit of this invention includes a first differential transistor and a second differential transistor with the emitters of these transistors being electrically connected to each other. An input signal (θ) is applied between a base of the first transistor and a base of the second transistor. A current source is connected to the emitters. The first transistor and the second transistor are configured so that a sine-converted output signal (sin θ) is generated at the collector of the first transistor and a reversed sine-converted output signal is generated at the collector of the second transistor.
0012With this configuration, the sine generation circuit can be constructed with a relatively simple circuit configuration.
0013A phase shift circuit of this invention, which shifts a phase of a coordinate input signal (x, y) by a phase shift input signal (θ) to generate an coordinate output signal (X, Y), includes a first sine generation circuit generating a sine-converted output signal (sin θ) of the phase shift input signal (θ) and a reversed sine-converted output signal (−sin θ) of the phase shift input signal (θ), a cosine generation circuit generating a cosine-converted output signal (cos θ) of the phase shift input signal (θ), a first multiplication circuit multiplying a first component of the coordinate input signal (x) by the cosine-converted output signal (cos θ), a second multiplication circuit multiplying a second component of the coordinate input signal (y) by the sine-converted output signal (sin θ), a third multiplication circuit multiplying the first component of the coordinate input signal (y) by the reversed sine-converted output signal (−sin θ), a fourth multiplication circuit multiplying the second component of the coordinate input signal (y) by the cosine-converted output signal (cos θ), a first addition circuit adding an output signal of the first multiplication circuit to an output signal of the second multiplication circuit, and a second addition circuit adding an output signal of the third multiplication circuit to an output signal of the fourth multiplication circuit. The first addition circuit provides a first component of the coordinate output signal (X), and the second addition circuit provides a second component of the coordinate output signal (Y).
0014With the above configuration, the construction of the phase shift circuit for tint adjustment using coordinate transformation becomes simple.
0015Furthermore, the sine generating circuit of the phase shift circuit includes a first differential transistor and a second differential transistor. The emitter of the first transistor and the emitter of the second transistor are electrically connected to each other and a current source is connected to the emitters of the first and second transistors. The phase shift input signal (θ) is applied between the base of the first transistor and the base of the second transistor. The first and second transistors are configured so that the sine-converted output signal (sin θ) is generated at the collector of the first transistor and the reversed sine-converted output signal (−sin θ) is generated at the collector of the second transistor.
0016The cosine generation circuit of the phase shift circuit includes a second sine generation circuit, which generates a sine-converted output signal (sin(θ/2)) of a signal corresponding to a half amount of the phase shift input signal (θ/2), a power circuit generating a signal corresponding to a second power of the sine-converted output signal (sin(θ/2)), an amplification circuit amplifying the signal corresponding to a second power of the sine-converted output signal (sin(θ/2)) by a factor of 2, and a subtraction circuit subtracting an output signal of the amplification circuit from a signal corresponding to a direct current component.
0017Each of the first sine generation circuit, the cosine generation circuit, and the first, second, third and forth multiplication circuits comprises a differential amplification device with a bipolar transistor.
0018Also, a tint adjustment circuit of this invention includes a demodulation circuit for demodulating a chrominance signal of a television signal in accordance with a carrier, and a phase shift circuit for shifting a phase of a first color difference signal and a second color difference signal outputted from the demodulator circuit. The tint is adjusted according to an amount of the phase shift of the first color difference signal and an amount of the phase shift of the second color difference signal.
0019According to the configuration described above, the tint adjustment of the television set can be easily performed on the component signal sent from an outside device such, as a DVD player.
0020The phase shift circuit of the tint adjustment circuit is a circuit for shifting a phase of a coordinate input signal (x,y) by a phase shift input signal (θ) to generate a coordinate output signal (X,Y). The phase shift circuit includes a sine generation circuit generating a sine-converted output signal (sin θ) of the phase shift input signal (θ) and a reversed sine-converted output signal (−sin θ) of the phase shift input signal (θ), a cosine generation circuit generating a cosine-converted output signal (cos θ) of the phase shift signal (θ), a first multiplication circuit multiplying a first component of the coordinate input signal (x) by the cosine-converted output signal (cos θ), a second multiplication circuit multiplying a second component of the coordinate input signal (y) by the sine-converted output signal (sin θ), a third multiplication circuit multiplying the first component of the coordinate input signal (y) by the reversed sine-converted output signal (−sin θ), a fourth multiplication circuit multiplying the second component of the coordinate input signal (y) by the cosine-converted output signal (cos θ), a first addition circuit adding an output signal of the first multiplication circuit to an output signal of the second multiplication circuit, and a second addition circuit adding an output signal of the third multiplication circuit to an output signal of the fourth multiplication circuit. The first addition circuit provides a first component of the coordinate output signal (X), and the second addition circuit provides a second component of the coordinate output signal (Y).
0021With the above configuration, the phase shit circuit can be formed by using the sine generation circuit, cosine generation circuit, and four multiplication circuits.
BRIEF DESCRIPTION OF THE DRAWINGS
<figref idref="DRAWINGS">FIG. 1</figref> is a block diagram of a demodulator for a chrominance signal used in an embodiment of this invention.
<figref idref="DRAWINGS">FIG. 2</figref> is a circuit diagram of a sine generation circuit of this embodiment.
<figref idref="DRAWINGS">FIG. 3</figref> is a block diagram of a phase shift circuit of this embodiment.
<figref idref="DRAWINGS">FIG. 4</figref> is a circuit diagram showing an example of the first sine generation circuit and the second sine generation circuit of FIG. <b>3</b>.
<figref idref="DRAWINGS">FIG. 5</figref> is a circuit diagram showing an example of the power generation circuit and the first through forth multiplication circuits of FIG. <b>3</b>.
<figref idref="DRAWINGS">FIG. 6</figref> is a block diagram of a conventional demodulator of chrominance signal.
DETAILED DESCRIPTION OF THE INVENTION
0028Next, an embodiment of this invention will be explained by referring to FIG. <b>1</b>. An ACC (auto color control) circuit <b>10</b> automatically adjusts the level of a composite chrominance signal from an input terminal <b>11</b>. A BPA (band-pass amplifier) <b>12</b> divides the composite chrominance signal outputted from the ACC circuit <b>10</b> into a chrominance signal and a burst signal.
0029A PLL (phase locked loop) circuit <b>13</b> has a phase comparator circuit, an LPF (low pass filter), and a VCO (voltage controlled oscillator) and generates a continuous wave, which is synchronized with the burst signal mentioned above. A phase shift circuit <b>14</b> generates two kinds of carriers for demodulation based on an output signal from the PLL circuit <b>13</b> (however, an adjustable phase shift is not performed). A demodulator <b>15</b> demodulates the chrominance signal separated and extracted by the BPA <b>12</b> based on the two carriers outputted from the phase shift circuit <b>14</b> and generates a B-Y signal and an R-Y signal.
0030Also, a DVD (digital video disc) <b>16</b> generates the B-Y signal and the R-Y signal as a video signal source. Switches <b>17</b> and <b>18</b> alternate the video signal sources. A tint circuit <b>19</b> (a phase shift circuit for tint adjustment) changes the phase of the B-Y signal and the R-Y signal from the switches <b>17</b>, <b>18</b> based on the controlling voltage for the tint adjustment, which is controlled by a viewer from outside. The controlling voltage is applied to a control voltage <b>20</b> for tint adjustment.
0031Next, the operation of the demodulator of the chrominance signal will be explained. The level of the composite chrominance signal, which is inputted from the input terminal <b>11</b>, is automatically adjusted by the ACC circuit <b>10</b>. The BPA <b>12</b> divides the composite chrominance signal, the level of which has been automatically adjusted, into the chrominance signal and the burst signal. The PLL circuit <b>13</b> has the phase comparator circuit, the LPF, and the VCO and generates the continuous wave synchronized with the burst signal.
0032The continuous wave is then converted to two kinds of carriers for demodulation by the phase shift circuit <b>14</b>, and applied to the demodulator <b>15</b>. The B-Y color difference signal and the R-Y color difference signal are obtained from the chrominance signal at the demodulator <b>15</b>, and applied to the switches <b>17</b>, <b>18</b>, respectively.
0033The B-Y color difference signal and the R-Y color difference signal are also applied to the switches <b>17</b>, <b>18</b> from the DVD <b>16</b>. One of the signals applied to each of the switches <b>17</b>, <b>18</b> is then applied to the tint circuit <b>19</b> based on the selection mode of the switches.
0034The tint circuit <b>19</b> shifts the phase of the inputted signal, enabling the color adjustment. In the system shown in <figref idref="DRAWINGS">FIG. 1</figref>, the phase shift is performed on the demodulated signal, that is, the color difference signal. Thus, it is possible to perform the color adjustment by using the signal from the DVD <b>16</b>.
0035Next, the principle of the tint circuit <b>19</b> will be explained. In order to obtain the coordinate output signal (X, Y) from the coordinate input signal (x, y) by the phase shift of θ, the input signal should be transformed based on the following coordinate transformation formula: <maths id="MATH-US-00001" num="00001"><math overflow="scroll"><mtable><mtr><mtd><mrow><mrow><mo>[</mo><mtable><mtr><mtd><mi>X</mi></mtd></mtr><mtr><mtd><mi>Y</mi></mtd></mtr></mtable><mo>]</mo></mrow><mo>=</mo><mrow><mrow><mrow><mo>[</mo><mtable><mtr><mtd><mrow><mi>cos</mi><mo></mo><mstyle><mtext> </mtext></mstyle><mo></mo><mi>θ</mi><mo></mo><mstyle><mtext> </mtext></mstyle><mo></mo><mi>sin</mi><mo></mo><mstyle><mtext> </mtext></mstyle><mo></mo><mi>θ</mi></mrow></mtd></mtr><mtr><mtd><mrow><mrow><mo>-</mo><mi>sin</mi></mrow><mo></mo><mstyle><mtext> </mtext></mstyle><mo></mo><mi>θcos</mi><mo></mo><mstyle><mtext> </mtext></mstyle><mo></mo><mi>θ</mi></mrow></mtd></mtr></mtable><mo>]</mo></mrow><mo></mo><mrow><mo>[</mo><mtable><mtr><mtd><mi>x</mi></mtd></mtr><mtr><mtd><mi>y</mi></mtd></mtr></mtable><mo>]</mo></mrow></mrow><mo>=</mo><mrow><mo>[</mo><mtable><mtr><mtd><mrow><mrow><mi>cos</mi><mo></mo><mstyle><mtext> </mtext></mstyle><mo></mo><mrow><mi>θ</mi><mo>·</mo><mi>x</mi></mrow></mrow><mo>+</mo><mrow><mi>sin</mi><mo></mo><mstyle><mtext> </mtext></mstyle><mo></mo><mrow><mi>θ</mi><mo>·</mo><mi>y</mi></mrow></mrow></mrow></mtd></mtr><mtr><mtd><mrow><mrow><mrow><mo>-</mo><mi>sin</mi></mrow><mo></mo><mstyle><mtext> </mtext></mstyle><mo></mo><mrow><mi>θ</mi><mo>·</mo><mi>x</mi></mrow></mrow><mo>+</mo><mrow><mi>cos</mi><mo></mo><mstyle><mtext> </mtext></mstyle><mo></mo><mrow><mi>θ</mi><mo>·</mo><mi>y</mi></mrow></mrow></mrow></mtd></mtr></mtable><mo>]</mo></mrow></mrow></mrow></mtd><mtd><mstyle><mtext>(Equation 1)</mtext></mstyle></mtd></mtr></mtable></math></maths>
0036That is, a transformation based on the equations X=x·Cos θ+y·Sin θ and Y=−x·Sin θ+y·Cos θ is carried out by the circuit. Furthermore, the following relationship between sine and cosine functions are well known: <maths id="MATH-US-00002" num="00002"><math overflow="scroll"><mtable><mtr><mtd><mrow><mrow><msup><mi>sin</mi><mn>2</mn></msup><mo></mo><mi>θ</mi></mrow><mo>=</mo><mfrac><mrow><mn>1</mn><mo>-</mo><mrow><mi>cos</mi><mo></mo><mstyle><mtext> </mtext></mstyle><mo></mo><mn>2</mn><mo></mo><mstyle><mtext> </mtext></mstyle><mo></mo><mi>θ</mi></mrow></mrow><mn>2</mn></mfrac></mrow></mtd><mtd><mstyle><mtext>(Equation 2)</mtext></mstyle></mtd></mtr></mtable></math></maths>
0037Since the following equations (3) and (4) can be obtained from equation (2), cos θ is given by the following equation (5). Accordingly, the cos θ is obtained from sin(θ/2). <br />2 sin<sup>2</sup>θ−1=−cos 2θ (Equation 3)<br />cos 2θ=1−2 sin<sup>2</sup>θ (Equation 4)<br /><maths id="MATH-US-00003" num="00003"><math overflow="scroll"><mtable><mtr><mtd><mrow><mrow><mi>cos</mi><mo></mo><mstyle><mtext> </mtext></mstyle><mo></mo><mi>θ</mi></mrow><mo>=</mo><mrow><mn>1</mn><mo>-</mo><mrow><mn>2</mn><mo></mo><mrow><msup><mi>sin</mi><mn>2</mn></msup><mo></mo><mrow><mo>(</mo><mfrac><mi>θ</mi><mn>2</mn></mfrac><mo>)</mo></mrow></mrow></mrow></mrow></mrow></mtd><mtd><mstyle><mtext>(Equation 5)</mtext></mstyle></mtd></mtr></mtable></math></maths>
0038Therefore, if the output signal sin(θ) can be generated from the input signal θ, a tint circuit, which is a phase shift circuit shifting the coordinate input signal (x,y) into the coordinate output signal (X,Y), can be obtained.
0039Next, the circuit for forming the output signal sin θ from the input signal θ will be explained. A differential amplifier shown in <figref idref="DRAWINGS">FIG. 2</figref> can generate substantially the same signal as the output signal sin θ from the input signal θ. In <figref idref="DRAWINGS">FIG. 2</figref>, θ is applied between input terminals <b>30</b>, <b>31</b> as an input signal. A constant current IO of a current source <b>32</b> goes through transistors <b>33</b>, <b>34</b> as an electric current Ic<b>1</b> and an electric current Ic<b>2</b>, respectively, based on the input signal θ.
0040Based on the relationship between the input and the output of the differential amplifier, and the relationship between the exponent function and tan h, the electric current Ic<b>1</b> and Ic<b>2</b> can be provided by the following equations (6), (7): <maths id="MATH-US-00004" num="00004"><math overflow="scroll"><mtable><mtr><mtd><mrow><msub><mi>Ic</mi><mn>1</mn></msub><mo>=</mo><mrow><mfrac><mrow><mi>α</mi><mo></mo><mstyle><mtext> </mtext></mstyle><mo></mo><msub><mi>I</mi><mn>0</mn></msub></mrow><mn>2</mn></mfrac><mo></mo><mrow><mo>{</mo><mrow><mn>1</mn><mo>+</mo><mrow><mi>tanh</mi><mo></mo><mstyle><mtext> </mtext></mstyle><mo></mo><mfrac><mi>λ</mi><mn>2</mn></mfrac><mo></mo><mi>θ</mi></mrow></mrow><mo>}</mo></mrow></mrow></mrow></mtd><mtd><mstyle><mtext>[Equation 6]</mtext></mstyle></mtd></mtr><mtr><mtd><mrow><msub><mi>Ic</mi><mn>2</mn></msub><mo>=</mo><mrow><mfrac><mrow><mi>α</mi><mo></mo><mstyle><mtext> </mtext></mstyle><mo></mo><msub><mi>I</mi><mn>0</mn></msub></mrow><mn>2</mn></mfrac><mo></mo><mrow><mo>{</mo><mrow><mn>1</mn><mo>-</mo><mrow><mi>tanh</mi><mo></mo><mstyle><mtext> </mtext></mstyle><mo></mo><mfrac><mi>λ</mi><mn>2</mn></mfrac><mo></mo><mstyle><mtext> </mtext></mstyle><mo></mo><mi>θ</mi></mrow></mrow><mo>}</mo></mrow></mrow></mrow></mtd><mtd><mstyle><mtext>[Equation 7]</mtext></mstyle></mtd></mtr></mtable></math></maths>
0041In equations (6) and (7), α represents a current ratio and λ is given by q/K·t, in which K is a Boltzman constant, t is absolute temperature and q is electric charge of an electron. Tan h θ is expressed by the following equation (8) developed in a Taylor series. <maths id="MATH-US-00005" num="00005"><math overflow="scroll"><mtable><mtr><mtd><mrow><mrow><mi>tanh</mi><mo></mo><mstyle><mtext> </mtext></mstyle><mo></mo><mi>θ</mi></mrow><mo>=</mo><mrow><mi>θ</mi><mo>-</mo><mrow><mfrac><mn>1</mn><mn>3</mn></mfrac><mo></mo><msup><mi>θ</mi><mn>3</mn></msup></mrow><mo>+</mo><mrow><mfrac><mn>2</mn><mn>15</mn></mfrac><mo></mo><msup><mi>θ</mi><mn>5</mn></msup></mrow></mrow></mrow></mtd><mtd><mstyle><mtext>[Equation 8]</mtext></mstyle></mtd></mtr></mtable></math></maths>
0042On the other hand, sin θ is expressed by the following equation (9) developed in another Taylor series. <maths id="MATH-US-00006" num="00006"><math overflow="scroll"><mtable><mtr><mtd><mrow><mrow><mi>sin</mi><mo></mo><mstyle><mtext> </mtext></mstyle><mo></mo><mi>θ</mi></mrow><mo>=</mo><mrow><mi>θ</mi><mo></mo><mstyle><mtext> </mtext></mstyle><mo>-</mo><mrow><mfrac><mn>1</mn><mrow><mn>3</mn><mo>×</mo><mn>2</mn></mrow></mfrac><mo></mo><msup><mi>θ</mi><mn>3</mn></msup></mrow><mo>+</mo><mrow><mfrac><mn>1</mn><mn>120</mn></mfrac><mo></mo><msup><mi>θ</mi><mn>5</mn></msup></mrow></mrow></mrow></mtd><mtd><mstyle><mtext>[Equation 9]</mtext></mstyle></mtd></mtr></mtable></math></maths>
0043Here θ is expressed in radian, and the amount of phase shift is relatively small. Typical phase shifts (θ) are 0.7 and 0.8. Therefore, the values provided by equation (8) and equation (9) are very close to each other, provided that the amount of phase shifts (θ) is small. There is only a slight difference in the coefficient of the third power of θ.
0044Therefore, equation (6) and equation (7) can be approximated by equation (10) and the equation (11), respectively. The number “1” in equations (10), (11) indicates a constant current, which is not affected by the input signal, or the DC component. <maths id="MATH-US-00007" num="00007"><math overflow="scroll"><mtable><mtr><mtd><mrow><msub><mi>Ic</mi><mn>1</mn></msub><mo>=</mo><mrow><mfrac><mrow><mi>α</mi><mo></mo><mstyle><mtext> </mtext></mstyle><mo></mo><msub><mi>I</mi><mn>0</mn></msub></mrow><mn>2</mn></mfrac><mo></mo><mrow><mo>{</mo><mrow><mn>1</mn><mo>+</mo><mrow><mi>sin</mi><mo></mo><mstyle><mtext> </mtext></mstyle><mo></mo><mfrac><mi>λ</mi><mn>2</mn></mfrac><mo></mo><mi>θ</mi></mrow></mrow><mo>}</mo></mrow></mrow></mrow></mtd><mtd><mstyle><mtext>[Equation 10]</mtext></mstyle></mtd></mtr><mtr><mtd><mrow><msub><mi>Ic</mi><mn>2</mn></msub><mo>=</mo><mrow><mfrac><mrow><mi>α</mi><mo></mo><mstyle><mtext> </mtext></mstyle><mo></mo><msub><mi>I</mi><mn>0</mn></msub></mrow><mn>2</mn></mfrac><mo></mo><mrow><mo>{</mo><mrow><mn>1</mn><mo>-</mo><mrow><mi>sin</mi><mo></mo><mstyle><mtext> </mtext></mstyle><mo></mo><mfrac><mi>λ</mi><mn>2</mn></mfrac><mo></mo><mi>θ</mi></mrow></mrow><mo>}</mo></mrow></mrow></mrow></mtd><mtd><mstyle><mtext>[Equation 11]</mtext></mstyle></mtd></mtr></mtable></math></maths>
0045Therefore, the differential amplifier shown in <figref idref="DRAWINGS">FIG. 2</figref> provides substantially the same signal as the output signal sin θ based on an input signal θ when a certain condition is met: i.e. the amount of phase shift is small.
0046Next, the circuit for shifting a phase of a coordinate input signal (x,y) by a phase shift input signal (θ) to generate a coordinate output signal (X,Y) by using the differential amplifier of <figref idref="DRAWINGS">FIG. 2</figref> is described with reference to FIG. <b>3</b>. In <figref idref="DRAWINGS">FIG. 3</figref>, a signal x (the color difference signal B-Y) is applied to an input terminal <b>40</b> and a signal y (the color difference signal R-Y) is applied to an input terminal <b>41</b>. The signal θ for tint adjustment is applied to a control terminal <b>42</b>.
0047A first sine generation circuit <b>43</b> in <figref idref="DRAWINGS">FIG. 3</figref> can be formed from the differential amplifier shown in FIG. <b>2</b>. The circuit should be configured according to equation 5 for obtaining cos θ. As seen from <figref idref="DRAWINGS">FIG. 3</figref>, the circuit for obtaining cos θ includes a second sine generation circuit <b>44</b> generating sin(θ/2), a power circuit <b>45</b> generating a signal (sin<sup>2 </sup>(θ/2)) corresponding to a second power of the output signal generated from the second sine generation circuit (sin(θ/2)), an amplification circuit <b>46</b> amplifying the output signal from the power circuit <b>45</b> by a factor of 2, and a subtraction circuit <b>47</b> subtracting an output signal of the amplification circuit <b>46</b> from 1 (an output signal from a direct current generation circuit <b>48</b>), and an amplifier <b>49</b> generating both positive and negative output signals.
0048With the above circuits, terminals <b>50</b>-<b>53</b> provide sin θ, −sin θ, cos θ, and −cos θ signals, respectively.
0049Here, the cos θ signal applied to a first multiplication circuit <b>54</b> and a forth multiplication circuit <b>55</b> can be obtained from the terminal <b>52</b>. Also, sin θ signal applied to a second multiplication circuit <b>56</b> and −sin θ signal applied to a third multiplication circuit <b>57</b> can be obtained from the terminals <b>50</b>, <b>51</b> respectively.
0050In this manner, “x·cos θ” is obtained at the output terminal of the first multiplication circuit <b>54</b>, “y·sin θ” at the output terminal of the second multiplication circuit <b>56</b>, and “x·sin θ” at the output terminal of the third multiplication circuit <b>57</b>. Additionally, “y·cos θ” is obtained at the output terminal of the forth multiplication circuit <b>55</b>. A first addition circuit <b>58</b> adds the output from the first multiplication circuit <b>54</b> to the output from the second multiplication circuit <b>56</b>, and a second addition circuit <b>59</b> adds the output from the third multiplication circuit <b>57</b> to the output from the forth multiplication circuit <b>55</b>.
0051With the circuit configuration shown in <figref idref="DRAWINGS">FIG. 3</figref>, the following relations can be obtained; X=x·cos θ+y·sin θ, Y=−x·sin θ+y·cos θ. Therefore, the coordinate input signal (x,y) can be converted into the coordinate output signal (X,Y) by the phase shift input signal (θ).
0052<figref idref="DRAWINGS">FIG. 4</figref> is a circuit diagram of the first sine generation circuit <b>43</b> and the second sine(θ/2) generation circuit <b>44</b> in FIG. <b>3</b>. In <figref idref="DRAWINGS">FIG. 4</figref>, the signal θ is applied between terminals <b>60</b>, <b>61</b> and supplied between a differential amplifier <b>64</b> having differential transistors <b>62</b>, <b>63</b> and a differential amplifier <b>67</b> having differential transistors <b>65</b>, <b>66</b>. The operation principle of the differential amplifier <b>64</b> is the same as that of the differential amplifier in FIG. <b>2</b>. That is, sin θ and −sin θ can be obtained at terminals <b>68</b>, <b>69</b>.
0053Diodes <b>70</b> and <b>71</b> are connected to emitters of the transistors <b>65</b>, <b>66</b> of the differential amplifier <b>67</b>. Through the diodes <b>70</b>, <b>71</b>, terminals <b>72</b>, <b>73</b> provide sin(θ/2) and −sin(θ/2), respectively.
0054In <figref idref="DRAWINGS">FIG. 3</figref>, the power generation circuit <b>45</b> and the first, second, third and forth multiplication circuits <b>54</b>-<b>55</b> include a multiplication circuit shown in FIG. <b>5</b>. In <figref idref="DRAWINGS">FIG. 5</figref>, one of the input signals is applied to input terminals <b>80</b>, <b>81</b>, and the other input signal is applied to terminals <b>82</b>, <b>83</b>. The multiplication of the both signals is performed.
0055The main part of the multiplication circuit includes a differential amplifier <b>86</b> having transistors <b>84</b>, <b>85</b> and a differential amplifier <b>89</b> having transistors <b>87</b>, <b>88</b>. The multiplication of the signal from transistor base and the signal from the emitter is performed.
0056Then, a part of the multiplication result is used as a collector current of the transistor <b>84</b> and a part of the multiplication result is used as a collector current of the transistor <b>88</b>. The polarity of the collector current of the transistor <b>84</b> is inverted at transistors <b>90</b>, <b>91</b> and then transmitted to an output terminal.
0057Also, the collector current of the transistor <b>88</b> is inverted at transistors <b>92</b>, <b>93</b> and transistors <b>94</b>, <b>95</b> and then transmitted to an output terminal. As a result, the multiplication result (y·sin θ), from which the direct current components are canceled out, is obtained at an output terminal <b>96</b>.
0058This invention enables the simple circuit configuration of sine generation circuit. Also the phase shift circuit using the coordinate transformation can be configured from the sine generation circuit, cosine generation circuit and four multiplication circuits.
0059Additionally, each of the sine generation circuit, cosine generation circuit and multiplication circuit can be configured from a bipolar transistor and the related resistors. Therefore, it is possible offer the phase shift circuit suitable for high-integration circuit.
0060Especially, the phase shift circuit of this invention is applicable to a phase shift circuit for shifting the phase of the first and second color difference signals outputted from the chrominance signal demodulation circuit. By adjusting the color in accordance with the amount of the phase shift provided by this phase shift circuit, the color adjustment of the television set can be easily performed using the component signals (Y, Cb, Cr) from an outside device such as DVD player.
0061The above is a detailed description of a particular embodiment of the invention which is not intended to limit the invention to the embodiment described. It is recognized that modifications within the scope of the invention will occur to a person skilled in the art. Such modifications and equivalents of the invention are intended for inclusion within the scope of this invention.
Contents4
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Every citation, both ways
| Document | Relation | Office | Cited during |
|---|---|---|---|
| US3961362A | Cites | United States of America | Search report |
| US4797732A | Cites | United States of America | Search report |
| US4932038A | Cites | United States of America | Applicant |
| US5006818A | Cites | United States of America | Search report |
| US6489848B2 | Cites | United States of America | Search report |
| US6636085B2 | Cites | United States of America | Search report |
| JPH01161907A | Cites | Japan | Applicant |
| JPH02111128A | Cites | Japan | Applicant |
9 members in 4 offices; this record represents the family
Priority claims10
| Document | Office | Kind | Date |
|---|---|---|---|
| 2001141192 | Japan | – | |
| 2001141193 | Japan | – | |
| 2001141192 | Japan | A | |
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| KR20020086297A | Republic of Korea | A | |
| JP2002335534A | Japan | A | |
| JP2002335535A | Japan | A | |
| CN1385958A | China | A | |
| US2002190763A1 | United States of America | A1 | |
| KR100468995B1 | Republic of Korea | B1 | |
| CN1198389C | China | C | |
| US6952239B2This record | United States of America | B2 | |
| JP4251787B2 | Japan | B2 |
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Numbers
- Publication
- 06952239
- Publication, DOCDB
- 6952239
- Publication, EPODOC
- US6952239
- Application
- 10142931
- Application, DOCDB
- 14293102
- Application, EPODOC
- US20020142931
Titles
- English
- Sine generation circuit, phase shift circuit and tint adjustment circuit
Patent term adjustment
- A delay
- +564 daysthe office missed an examination deadline
- Net adjustment
- 564 days
Classification
- CPC, 2
- H04N9/643
- H04N9/64
- IPC, 1
- H04N9 64
- USPC, 3
- 348654000
- 348638000
- 348E09040